Newbie CNC Router 4th Axis - Post Process to MACH3

[rwetzler]

Recently acquired a 6040 CNC mill with a 4th axis which I've been tinkering with and having problems getting it run properly in MACH3. I can manually command it fine, all good there. I created a simple 1/2" dia. shaft with 2 flats 90 deg. apart (typical system for sprocket mounting, etc). When I run the simulation in Fusion 360 it looks great but in Mach3 the tool path is different and I can't wrap my head around how to solve it. I've included the file showing the 2d pocket profile I'm using, etc. I'm doing something wrong in MACH3 I suppose. I'll try to upload a short video of it running the code. It's offset from the work piece to keep it from crashing into the stock for the time being.
Any help would be greatly appreciated. I changed the file extension to .txt so the gcode file would upload.
.f3d and .tap files attached for ref.

[thaont.cnc]

I don't know what is the problem. I think, you change G54 G0 Z0 to G53 G0 Z0

This is gcode my post.

[rwetzler · Accepted solution]

I ended up just using  a work around to solve the problem. After the first flat is machined on top, insert a 90 degree rotation in the code and repeat the same code again. I'm sure there is a proper way to accomplish this but didn't get much help from the forum so for the time being this is the way to mill two flats on a shaft 90  degrees apart.

I attached the code for other newbies that might be struggling with this issue.

[engineguy]

@rwetzler 

Just a tip for starters, if you give yourself the "question resolved kudos" then people think it has been sorted and of course don`t come and have a look to help out so that`s probably why you didn`t get much interest from the Forum.

Anyway, 4th Axis, usually not a problem if correctly set up, I have made some adjustments to your setup on the assumption that you are probably like most Router users and have set your 4th Axis to revolve around the Y Axis on your machine, if I am wrong with this then come back and I will change it to what you need (X Axis ??).

First thing about 4th axis is that the part is going to revolve around an axis so the Setup must be done to suit and the WCS must be the center point of the rotation, see images below, first image is of how I have set the Orientation and you can see it is set to the center of rotation around the Y Axis, the second image shows the code that is generated loaded into Mach3, what Mach3 does if the operations are the same it only shows them in the same plane.

The code runs correctly in Mach3, it does the top pocket then moves the A axis -90 degrees and then does the pocket again, see Screencast link  https://autode.sk/3DeOJTa   and attached modified file 🙂

[rwetzler]

Thanks for sharing. I wasn't able to open your fusion file. I get a error "You are in process installing an update that is required to open Test Shaft 4th Axis v1-MOD v2". Strange because I'm not installing an update. I did go into my setup and changed the centerline of the model to the origin. I do have my 4th axis running on the X-Axis. After making the changes I ran a few air runs and it worked fine.  I came from an open builds system I put together a few years ago running on Chilipper so getting use to my new router and Mach3 has been quite a challenge. Looking forward to getting the hang of the 4th axis. I've been using G55 on most of my setups but when try to run a job the toolpath shows me being in the corner at the Home position of 0,0,0 instead of the middle of the table at my G55 zero position. Don't have limit switches, so using the soft limits feature. The job will run fine it's just that the toolpath viewer not showing correctly. At any rate thanks for your help!